On the evening of August 11, at the site of the first phase of the North Utility Corridor Water Supply Project in the Xiong’an New Area, Hebei Province, a 710-meter-long water supply pipeline — assembled from 58 steel pipes each measuring 1.4 meters in diameter — was successfully pulled into place after seven hours of continuous effort, crossing beneath the Baigou Diversion River. This marked the completion of the nation’s largest-diameter steel pipe directional drilling pullback operation in a water supply project.
The first phase of the North Utility Corridor Water Supply Project in Xiong’an New Area has a total length of 34.29 kilometers, connecting the Xiong’an Start-up Area with the Xiong’an High-speed Railway Station area. China TIESIJU Civil Engineering Group, a subsidiary of CREC, undertook 21.25 kilometers of pipeline construction, including pipeline laying, shaft construction, and installation of electromechanical and metal structures. This section includes 18.55 kilometers of open-cut works, 1.995 kilometers of pipe jacking, and 710 meters of directional drilling pullback.
To meet the high-precision requirements of crossing beneath the Baigou Diversion River in a complex geological environment, the project team adopted a 12-step reaming process. First, a pilot drill rod equipped with a signal transmitter navigated 710 meters underground along the designed route under the guidance of precision instruments, creating a guiding path. Then, a powerful directional drilling machine successively replaced drill heads of increasing sizes to ream the borehole step by step. Meanwhile, specially formulated slurry was injected at high pressure into the borehole to quickly form a solid protective membrane on the bore wall, addressing the challenge of potential collapse in soft soil strata. Through the combined approach of precision guidance, stepwise reaming, and slurry wall protection, the team successfully created a smooth and stable underground borehole with a diameter of approximately 2.1 meters, clearing the way for the 710-meter-long water supply pipeline.
